Clean masonry is worth a surprising amount on a house, and cleaning is one of the easiest ways to do permanent damage to it.
Pressure is not the tool
The phrase power washing does most of the harm here. Brick has a hard fired outer face, and that face is what keeps water out. High pressure strips it off, leaving the soft, porous interior exposed. It also blasts mortar out of the joints. The damage is not always obvious on the day, and it shows up over the following few winters as spalling.
Most brick should be cleaned well below 1,000 psi. The chemistry should be doing the work, not the pressure.
What we are actually removing
- Efflorescence. White salt deposits brought to the surface by water moving through the wall. The deposit itself is cosmetic, but it is evidence of water in the masonry, so we look for the source.
- Biological growth. Green and black algae and moss on shaded north walls. Straightforward to remove with the right detergent.
- Carbon and soot. Decades of atmospheric grime, common closer to the city. Needs an appropriate cleaner and dwell time.
- Rust and mineral staining. Usually running from steel lintels, railings or downspouts. Needs a specific treatment, and it is worth fixing the source at the same time.
- Paint. Removable with masonry-safe chemical strippers. Slow work, and worth doing properly.
Always a test patch
Different brick responds differently, and previous repairs can react in unexpected ways. We clean a small hidden area first, check the result, and adjust before touching the front of the house.
One useful side effect: clean brick shows its real condition. It is common to finish a cleaning and immediately be able to point out which joints need repointing, which were invisible under the grime.
Signs you need this work
- White chalky deposits on the brick face
- Green or black biological growth on shaded walls
- Dark carbon or soot staining, especially near the city
- Rust or mineral staining running down from steel or downspouts
- Paint peeling off brick that should never have been painted
- General dinginess that makes sound brick look neglected
What's included
- Test patch in an inconspicuous area before committing to a method
- Appropriate cleaner selected for the stain and the substrate
- Controlled pressure, low enough to protect the brick face
- Windows, plants and adjacent materials protected and rinsed
- Efflorescence treatment addressing the moisture source, not just the deposit
- Optional breathable water repellent after cleaning
How we do it
- 1
Test first
We clean a small, hidden patch and check the result before touching the visible elevations.
- 2
Protect
Plantings, windows, fixtures and adjacent materials get covered and pre-wetted.
- 3
Clean
Correct chemistry, controlled pressure, worked top to bottom and rinsed thoroughly.
- 4
Assess what is underneath
Clean brick shows its condition honestly, so we will flag any joints or units that need attention.
Common questions
Can power washing damage brick?
Yes, easily. High pressure strips the hard fired face off brick and blows mortar out of the joints. Most brick should be cleaned at well under 1,000 psi with the right chemistry doing the work rather than the pressure.
What is the white powder on my brick?
Efflorescence: dissolved salts carried to the surface by water moving through the wall, left behind when the water evaporates. It is cosmetic in itself, but it tells you water is getting into the masonry, and that is worth investigating.
Can you remove paint from brick?
Usually, with masonry-safe chemical strippers and a lot of patience. Never with blasting. Be aware that brick painted decades ago may have absorbed paint into the face, and some ghosting can remain.
Should I seal my brick after cleaning?
Only with a breathable siloxane water repellent, and only where it is warranted. Film-forming sealers trap moisture inside the wall and cause far more damage than they prevent.